Object-oriented programming systems utilize collections of computer programming components executing within a system to form applications that provide a desired set of functionality. Components that possess authority to gain access to components present on a given system typically can identity and activate all other components that are presented on this system. This fact may allow processing systems to behave in manners that are different that initially intended as components attempt to access components that were not intended to be activated by a particular component.
This potential deficiency in component-based systems typically arises when a component in one collection of components that is viewed to be a single application attempts to access components resident within a second application resident on the same computing system. No mechanism exists in current component based systems to confine activation calls for components between these applications to a small, well-defined set of access points. As such, component based systems may be vulnerable to several different types of inappropriate and unauthorized behavior by applications.
Computing systems developed prior to the creation of component-based systems did not necessarily suffer this system deficiency as executable sets of processing modules were linked together into a single executable module that accessed processing resources through the use of system calls to an operating system. As such, the entry points to executable modules was both well defined and under the control of a system administrator. Access to these system calls could be monitored and limited if appropriate.
This situation is different in component based computing systems in which one component may call a second component which in turn may call a third component. This sequence of calls may extend to any number of levels. The various components may be developed by different individuals for completely different purposes. The net result of these combinations of component calls may not be well understood or easily traceable until inappropriate behavior has occurred.